Nutella lovers, this cake recipe is the stuff your decadent dreams are made of: rich chocolate hazelnut Nutella cake with creamy Nutella frosting and fudgy Nutella ganache, adorned with Ferraro Rocher candy. And it's easier to make than you might think; the cake batter whips up by hand, and the frosting takes just 5 minutes!
Preheat the oven to 350F. Butter and flour a 6-inch round springform pan. Line the bottom with parchment paper that’s been trimmed to fit inside.
Whisk together the flour, sugar, cocoa powder, baking soda, salt, and espresso powder in a large bowl. Whisk together the Nutella and hot water in a medium bowl; once combined, whisk in the oil, egg, molasses, vanilla, and hazelnut extract. Add the wet ingredients to the dry all at once, and whisk to combine. Be careful not to over-mix.
Transfer the batter to the prepared pan. Bake until a toothpick inserted in the center comes out clean, about 45 minutes. Let the cake cool for 15 minutes in the pan, then turn it out onto a wire rack to cool to room temperature (about 30 minutes), and then refrigerate 15 minutes to chill.
For the Nutella Buttercream Frosting:
Add the butter and Nutella to a large bowl, and use a handheld electric mixer to beat until well-combined. Sift in the powdered sugar, cocoa powder, and salt, and beat until fully incorporated (the mixture will be lumpy). Lastly, add the cream and beat until smooth and creamy.
If the buttercream is too thick, add a splash more cream; if it’s too runny, add a little more powdered sugar.
Set aside about 1 cup of buttercream to decorate the top of the cake.
To Assemble the Cake:
Once the cake is cooled completely, cut it in half horizontally (so you can make a 2-layer cake).
Put 1 cake half onto a cake stand. Spread about 3/4 cup of buttercream on top.
Place the second cake half on top of the buttercream.
Frost the sides and top of the cake evenly with the remaining buttercream (keeping the reserved 1 cup of buttercream to decorate the top later).
Chill the cake in the fridge for 15 minutes.
For the Nutella Ganache:
Once the cake is chilled, make the ganache.
Stir together the Nutella and warm cream in a small bowl until smooth. (You can briefly heat it up to help it combine if need be.) Let it cool until the ganache is no longer warm, but is still pourable, about 15 minutes (it can’t be warm or it will melt the buttercream).
Pour the ganache on top of the cake, letting it drip decoratively down the sides. Chill in the fridge for 1 hour before decorating the top of the cake (this is necessary so the frosting rosettes don’t slide off the top).
To Decorate the Cake:
Once the ganache is set, you can decorate the top. Put the reserved 1 cup buttercream into a piping bag fitted with an open star piping tip. Pipe 6 to 8 rosettes evenly spaced around the outer edge of the cake on top.
Unwrap the Ferraro Rocher candies and put 1 on top of each of the 8 buttercream rosettes.
Sprinkle the chopped hazelnuts decoratively around the top of the cake.
Serve.
Notes
Nutella in the Cake Batter: This is completely optional. If you leave it out, you’ll have a fluffy, moist chocolate cake. If you add it, you’ll have a denser moist chocolate cake with a texture that’s like a cross between brownies and cake.
Make Ahead (Cake): You can make the cake the day before. Once it's cool, wrap it and leave it at room temperature overnight.
Make Ahead (Frosting): You can make the Nutella frosting well in advance. Store it in an airtight container in the fridge for up to 1 week, or in the freezer for up to 2 months. When you want to use the buttercream, let it sit at room temperature for 20 minutes to soften, and then beat it in a stand mixer or using an electric hand mixer until smooth and creamy.
Storage: Once the cake is frosted and decorated, you can store it wrapped well in the fridge for up to 3 days before it starts to dry out. After refrigerating, let the cake sit at room temperature for 15 to 20 minutes before serving so the frosting can soften.